Tight junctions are altered upon loss of desmoplakin.

(A-B′) Calcium was added to WT and DP-null keratinocytes, and cells were fixed at various time points and stained for tight junction proteins occludin (red) and ZO-1 (green). Scale bar, 10 µm. (C,D) ZO-1 staining of WT and DP-null keratinocytes at 3 hour after calcium switch. (E) Co-stain for ZO-1 (red) and E-cadherin (green) in DP null keratinocytes 3 hours after calcium switch. (F) RNA was isolated from WT and DP-null keratinocytes, and RT-PCR for several claudins was performed. ***, p<.0005, **, p<.005. n = 3. (G-I) Western blot analysis of total levels of claudin-1 and β-actin in lysates from cultured keratinocytes (G,H) and from isolated epidermis (I). (J,K) Claudin 1 staining of WT and DP-null keratinocytes 24 hours after calcium shift. (L,M) Immunofluorescence analysis of claudin 1 (green) and β4-integrin (red) in wild type (L) and desmoplakin conditional null epidermis (M). Scale bars are 10 µm.